1、Pt(NH3)2Cl2 cis 二氯二氨合铂(II) trans - 二氯二氨合铂(II)二、化学结构异构现象,大致分为五类:Ionization isomerism, Hydrate isomerism, Linkage isomerism, Coordination isomerism,Polymerization isomerism.1Ionization isomerism (1) Two coordination compounds which differ in the distribution of ions between those directly coordinated
2、and counter-ions present in the crystal lattice are called ionization isomers. (2) e.g. Cr(NH3)5BrSO4 and Cr(NH3)5SO4Br2Hydrate isomerism (Solvent isomerism) (1) Hydrate isomerism is similar to ionization isomerism except that an uncharged ligand changes from being coordinated to a free-lattice posi
3、tion whilst another ligand moves in the opposite sense.(2) e.g. Cr(H2O)6Cl3 ,Cr(H2O)5ClCl2H2O ,Cr(H2O)4Cl2Cl2H2O 3Linkage isomerism (1) The first example of this type of isomerism was provided by Jfrgensen, Werners contemporary. His method of preparation was as follows: (2) It deals with a few ligan
4、ds (ambidenatate) that are capable of bonding through are type of donor atom in one situation not a different atom in another complex. Some authors refer to this type of isomerism as “structural isomerism” but inasmuch as all isomerism is basically “structural” , the term linkage isomerism is prefer
5、able. (3) e.g. and and 4Coordination isomerism (1) This may occur only when the cation and anion of a salt are both complexes, the two isomers differing in the distribution of ligands between the cation and anion (2) e.g. and and and (3) Coordination position isomerismIn this form of isomerism the d
6、istribution of ligands between two coordination centers differse.g. and 5Polymerization isomerism (1) Strictly speaking, polymerization isomerism, in which n varies in the complex MLmn is not isomerism. It is included in this list because it represents on additional way in which an empirical formula
7、 may give incomplete information about the nature of a complex. (2) For example, all members of the following series are polymerization isomers: 三、立体异构现象 (Stereo Isomerism)1几何异构现象 (Geometrical isomerism) (1) 配合物的配位数与几何构型的关系 (The relationship between coordination number of complexes and geometrical s
8、tructure.)a两配位:直线型 (linear) 、b三配位:平面三角型 (triangle) c四配位:平面四方 (square planar) ; 正四面体 (tetrahedron) d五配位:三角双锥 (trigonal bipyramid) 、 四方锥 (square pyramid) e六配位:正八面体 (octahedron) 、 三棱柱 (trigonal prism) f七配位:五角双锥 (pentagonal bipyramid) 带帽三棱柱 (the one-face centred trigonal prism) 带帽八面体 (the one-face centr
9、ed octahedron)g八配位:立方体 (cube) (立方烷) 四方反棱柱(square anti prism) 十二面体(dodecahedron) 我们将讨论四、五、六配位配合物的几何异构现象 (2) 决定配合物几何异构体数目的因素: a空间构型:例如正四面体几何构型不存在几何异构体。这是因为正四面体的四个顶点是等价的。空间构型中等价点越多,几何异构体越少。b配体种类:在配合物中配体种类越多,几何异构体越多。例如,八面体配合物:Ma6(一种),Mabcdef(15种) (a、b、c、d、e、f为单齿配体)c配体的齿数:双齿配体的两个配位原子只能放置在结构中的邻位位置上,不能放置在对
10、位位置上(跨度大,环中张力太大),即:d多齿配体中配位原子的种类(及环境):种类越多,环境越复杂,几何异构体越多。 (3) 几种常见配位数的配合物的几何异构现象 a四配位:(i) 正四面体:不存在几何异构体(ii) 平面四方:M 中心体 , AA, AB 双齿配体 ,a, b, c 单齿配体。配合物类型()几何异构体数目123 b五配位:三角双锥几何异构体数目54710四方锥几何异构体数目6915 c六配位:只讨论正八面体几何构型:Ma4e2(Ma4ef)Ma3d3Ma3defMa2c2e2MabcdefM(AB)2ef (4) 确定几何异构体的方法 直接图示法a只有单齿配体的配合物 以Ma2cdef为例 (9种):第一步,先确定相同单齿配体的位置
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